const fp = require('lodash/fp')
// import fp from 'lodash/fp';

// horsepower 马力， dollar_value 价格，in_stock 库存

const cars = [
  {name: 'Ferrari FF', horsepower: 660, dollar_value: 700000, in_stock: true},
  {name: 'Spyker C12 Zagato', horsepower: 650, dollar_value: 648000, in_stock: false},
  {name: 'Jaguar XKR-S', horsepower: 550, dollar_value: 132000, in_stock: false},
  {name: 'Audi A8', horsepower: 525, dollar_value: 114200, in_stock: false},
  {name: 'Aston Martin One-77', horsepower: 750, dollar_value: 1850000, in_stock: true},
  {name: 'Pagain Huayra', horsepower: 700, dollar_value: 1300000, in_stock: false},
]

// 练习1
const isLastInStock = fp.flowRight(fp.prop('in_stock'), fp.last)

console.log(isLastInStock(cars))


// 练习2
const firstCarName = fp.flowRight(fp.prop('name'), fp.first)

console.log(firstCarName(cars))

// 练习3
let _average = function (xs) {
  fp.reduce()
  return fp.reduce(fp.add, 0, xs) / xs.length
}

const getDollarValueOfEveryCar = fp.map((car) => car.dollar_value)
const averageDollarValue = fp.flowRight(_average, getDollarValueOfEveryCar)

console.log(averageDollarValue(cars))

// 练习4
let _underscore = fp.replace(/\W+/g, '_')

const sanitizeNames = fp.map(fp.flowRight(_underscore, fp.lowerCase))

console.log(sanitizeNames(['Hello World']))